Typically liquid crystal displays (LCDs) display images by varying the amount of light that passes through liquid crystal cells of the liquid crystal panel. FIG. 1 is a diagram illustrating a conventional LCD 100. LCD 100 includes a liquid crystal layer 102, which is the “active layer” in the LCD. Liquid crystal layer 102 determines the amount of light which passes through by rotating the polarization of the light passing though the layer. Liquid crystal layer 102 rotates the polarization of the incoming light by applying a local voltage to different cells within liquid crystal layer 102.
Liquid crystal layer 102 is placed between two polarizing filters 104 and 106 that have a 90 degree rotation in their polarization axis. When placed between polarizing filters 104 and 106, liquid crystal layer 102 determines the amount of light passing through by rotating the polarization of the light to be aligned or misaligned with the polarization axis of filter 106. Since each cell of liquid crystal layer 102 may be controlled individually, each cell of liquid crystal layer 102 behaves as a voltage controlled valve letting though more or less of the incoming light, depending on the voltage applied to that cell. Liquid crystal layer 102 is supported by glass layers 112.
LCD 100 generates different colors by using a monochrome light backlight 108 with color filter 110. To achieve different colors, each LCD pixel includes three color filters 110 which cover three adjacent cells of liquid crystal layer 102, each cell being individually controlled. In this scheme two-thirds of the light making it though liquid crystal layer 102 is absorbed by color filter 110. The blue filter totally absorbs the incident green and red component, the green filter all the blue and red, and the red filter all the green and blue. Accordingly, backlight 108 must be power at a high intensity in order to produce video at a suitable brightness.